Pharmacoscintigraphy: 研究藥物在人體的釋放與吸收之技術   全文下載

Pharmacoscintigraphy: Techniques for Studying Drug Release And Absorption in Humans

藥物在體內胃腸道內的釋放與吸收其程序相當複雜，受許多變數影響。在藥物的研究，賦形劑的處理與處方的機械性設計方面已有相當多的努力，然而影響釋放與吸收程序的生理因素方面則所知有限。處方於胃腸道內的情形可用伽瑪放射性測定儀測定單同一位素而得知，然而，此技術有所限制：（1）標的物於胃腸中的位置難以確定，（2）由於組織的衰減與同位素的移動而難以定放射性的量，（3）難以區分放射性核種是固態或溶解物，（4）放射性標識的劑型難以製備，（5）無論是藥物或賦形劑都無法以核種標識。上述這些問題某部份則可以雙同位素，等比中項測定，角度變動係數，中子活性及藥動技術予以克服，數種放射性技術（scintigraphic techriques）與藥動（pharmacokinetics）的結合，可徹底地改進數據資料的品質，因此，新名詞'pharmacoscintigrapjy'於焉而生。pharmacoscintigraphy之應用可更進一步以其他的技術補足，如定安性同位數與氣相屬析質譜，酸鹼值檢查，及胃腸道插管，這些技術可單獨使用或同時與pharmacoscintigraph使用，以提供吾人有關人類藥物釋放與吸收之完整狀況。

In vivo drug release and absorption in the gastrointestinal tract are governed by a complex process subject to many variables. Extensive efforts were spent in studying the durg and manipulating the excipient and mechanical design of the formulation but little is known regarding the physiological factors that influence the release and absorptive processes. Understanding of the behavior of formulation inside the GI tract has been made by gamma scintigraphy using a single isotope. However, the technique is suffering from several limitations: (1) anatomical location of the object is difficult to determine; (2) quantification of radioactivity is difficult due to tissue attenuation and movement of isotope; (3) cannot distinguish between a radionuclide present as a solid or as a solute; (4) preparation of the radiolabeled dosage forms are problematic; and (5) neither the drug nor the excipients can be labeled with nuclide. These problems can be partly alleviated by using dual isotopic, geometric mean measurement, perturbed angular correlation, neutron activation, and pharmacokinetic techniques. Combining several scintigraphic techniques with pharmacokinetics can drastically improve the quality of the data. Thus, the term pharmacoscintigraphy was coined. The application of pharmacoscintigraphy can be further supplemented by other techniques such as stable isotope with gas chromatography-mass spectrometry, pH monitoring and gastrointestinal intubation. Those techniques can be used either independently or simultaneously with pharmacoscintigraphy to provide us with a full picture of durg release and absorption in humans.